Science and Beer — How yeast plays an important role

Many people will tell you that if you can cook, you can make beer. But masters of the craft know that creating the perfect flavor is a chemical process more than anything else. Dr. Michael Lentz, a biology professor at the University of North Florida, is putting his Ph.D in microbiology to use in an extensive research study on yeast, one of the key ingredients in homebrewing.

Lentz has been a professor at UNF for 18 years, but has been a craft beer enthusiast for much longer. Lentz was introduced to homebrewing while working on his postdoctoral work at the University of California, Berkeley, when he competed in a beer-brewing showdown with other postgraduate students for fun.

Since then, Lentz has been a homebrewer, experimenting with different brewing methods and ingredients in a microbrewery in his home. He is also actively involved in local brewing associations, which is how he met Eric Luman, co-founder of the Green Room Brewing in Jacksonville Beach.

Two years ago, Luman, who was a student at UNF at the time, approached Lentz about overseeing his senior research project. The project focused on researching the cell biology of yeast, a single-celled microorganism that is easily manipulated in the lab.

The project has grown into a two-year independent research study dubbed the, “Yeast Project.” The study has led to a collaboration with Green Room Brewing and has also garnered attention and funding from UNF and the American Homebrewers Association.

Currently, the research team’s main goal is to clone and characterize genes of yeast to make proteins in large enough quantities to run lab tests and see how they work. Cloning these particular genes has, to Lentz’s knowledge, never been done before.

While the researchers are more focused on the biochemistry behind the fungi, they are also utilizing brewing knowledge and techniques in their study. Most homebrewers do not have access to the facilities and resources that Lentz and his students do for yeast extraction. UNF has given the team a unique opportunity in that way.

“We have been using the local yeast in homebrewing, and we are finding that some yeast provide unique flavors for our beer,” Lentz said.

Yeast is a key ingredient in brewing beer because it uses the sugar to create both alcohol and carbon dioxide, as well as produce many other flavor components. Two different varieties of yeast are used in homebrewing: top-fermenting yeast for ales and bottom-fermenting yeast for lagers. Ale is much easier to ferment because the brewing process only takes two weeks and the temperature is not as hard to control as lager.

Yeast is the last component added to a brew that provides flavor, so finding the right strain of yeast for a batch is essential in craft brewing. Extracting yeast from fruit have provided Lentz and his team with interesting strains. Yeast found in fruit is also easy to find, as anything high in sugar content is likely to have high-yeast content as well. The team has studied yeast strains in all different kinds of fruit, from berries to citrus, but they haven’t yet discovered if the yeast is consistent.

What they do know is that common yeast, which is used in mass beer production, doesn’t provide a wide range of flavor. It also doesn’t give brewers the option to use local ingredients.

“A lot of craft brewers are passionate about using fresh and local products in their brewing process,” Lentz said. “If we can get all of the other ingredients in a batch locally, why not the yeast, too?”

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